show3d-methods              package:dti              R Documentation

_M_e_t_h_o_d_s _f_o_r _F_u_n_c_t_i_o_n _s_h_o_w_3_d _i_n _P_a_c_k_a_g_e _d_t_i

_D_e_s_c_r_i_p_t_i_o_n:

     The function provides 3D visualization of '"dtiTensor"' and
     '"dtiIndices"' objects using the '"rgl"'-package. Functionality of
     the rgl-package allows to rotate and zoom the displayed object.

_U_s_a_g_e:

       ## S4 method for signature 'dtiTensor':
       show3d(obj, nx=NULL, ny=NULL, nz=NULL, center=NULL, method=1, level=0, scale=.25, bgcolor="black", add=FALSE, subdivide=2, smooth=TRUE, maxobjects=729, ...)
       ## S4 method for signature 'dtiIndices':
       show3d(obj, index="FA", nx=NULL, ny=NULL, nz=NULL, center=NULL, method=1, level=0, bgcolor="black", add=FALSE, lwd=1, ...)

_A_r_g_u_m_e_n_t_s:

     obj: An object of class 'dtiTensor' or 'dtiIndices' 

      nx: Number of voxel in x-direction

      ny: Number of voxel in y-direction

      nz: Number of slices

  center: Vector of length 3 specifying the center of the data cube
          (class 'dtiTensor') or center of display (class 'dtiIndices')

  method: 'method==1' and 'method==2' specify two different color
          schemes for  directional FA-maps.

   level: Minimal FA value of tensors.

   scale: Scale factor for the size of ellipsoids

 bgcolor: Backgroundcolor for rgl-display

     add: If true information is added to the current device, otherwise
          a new device is opened.

subdivide: Level of subdivisions for meshing of ellipsoids, see package
          rgl.

  smooth: Use smooted surfaces, see package rgl.

maxobjects: Maximal size of data cube (in voxel) to display

   index: Eiter '"FA"' for fractional anisotropy index or  '"GA"' for
          geodesic anisotropy index.

     lwd: Line width to use.

     ...: Additional parameters passed to function 'rgl.par' from the
          rgl-package.

_V_a_l_u_e:

     The function returns the number of the current rgl-device.

_M_e_t_h_o_d_s:



     _o_b_j = "_A_N_Y" Returns a warning 

     _o_b_j = "_d_t_i_I_n_d_i_c_e_s" Objects are visualized as a collection of line
          segments with location given by the voxel center, orientation
          and color determined by the main direction of inisotropy and
          length corresponding to either fractional or geodesic
          anisotropy as specified in 'index'. 

          Displayed objects are restricted to voxel with an fractional
          (geodesic) anisotropy larger than 'level'.

     _o_b_j = "_d_t_i_T_e_n_s_o_r" Ellipsoids are visualized at the voxel centers.
          Orientation and size correspond to the tensor values, color
          is determined by the main direction of anisotropy using the
          colorsceme specified with 'method'. The fractional anisotropy
          value is coded as transparency. The value of 'maxobjects'
          limits the size of datacube and may be increased on hardware
          with suitable graphics capabilities. 

          Displays can be closed using function 'rgl.close'

_A_u_t_h_o_r(_s):

     Karsten Tabelow tabelow@wias-berlin.de
       J\"org Polzehl polzehl@wias-berlin.de

_S_e_e _A_l_s_o:

     'dtiIndices-methods', 'dti.smooth',  'dtiTensor', 'dtiIndices'

_E_x_a_m_p_l_e_s:

       ## Not run: demo(dti_art)

